Marvel fans are well aware that the superhero studio hates spoilers. Hence why Rachel Weisz looked so nervous when she landed in this tricky situation.

Rachel Weisz is set to play Melina in the upcoming 'Black Widow' opposite Scarlett Johansson, reprising the titular superhero role.

When introducing the actress onto his talk show, Jimmy Kimmel said that she'll be playing Melina Vostokoff in the movie - Melina's surname had not previously been revealed.

"I think we're not allowed to say Melina's second name," the actress told Kimmel, looking nervous. "I think we're prohibited from saying Melina's second name, I think it's a Marvel Cinematic secret."

The talk show host asked if he'd really just ruined a secret. Rachel Weisz answered: "I believe so."

They spoke about coping during the pandemic and the actress spoke about her daughter.

They did get around to talking about Melina again. Weisz revealed that the character is a highly skilled Black Widow spy and scientist. Melina also speaks 25 languages and has a pig farm.

Regarding Marvel's spoiler culture and Kimmel's mess up, he asked if there were any specific rules for what she could or couldn't talk about.

"There's a list, I lost it. The one thing I do remember is — I know the big spoilers which I'm obviously not going to say — my character's second name is like —," Rachel Weisz said, miming zipping her lips.

"That's out there. That's public knowledge," Kimmel answered. He added that maybe she should have kept the list.

Rachel Weisz responded perfectly: "You know what, you're right. I'm going to have a drink."

Here's the full interview.

The release date of 'Black Widow' is July 9th. It will show in cinemas and stream through Disney+ with Premier Access.